Optical wavefronts are subject to the optical effects of distortion and degradation when passed through certain mediums such as the atmosphere. The atmosphere is subject to turbulence, for example, due to different temperature layers and different winds speeds, to name a few.
Distortion and degradation of optical wavefronts may also occur during reconstruction of the wavefronts by an optical system. This is known as optical aberration wherein imperfections result from image reconstruction. Optical aberrations include what is known as monochromatic and chromatic. A monochromatic aberration is caused by the geometry of the lens used in the optical system whereas chromatic aberrations are caused by dispersion—a failure of the lens to focus all colors to the same convergence point. Specific types of distortion and degradation include what is known as blurring, scintillation, and speckle.
Both turbulence and aberration compromise the vision and resolution of optical images produced by optical systems. Optical systems include, for example, telescopes, microscopes, binoculars, cameras, interferometers and retinal imaging systems.
To improve the performance and reduce distortion and degradation of optical images produced by optical systems, adaptive optics technology is used. More particularly, adaptive optics technology attempts to correct distortions and degradations using a wavefront sensor, a deformable mirror that lies in the optical path, and a computer apparatus that receives input from the wavefront sensor. The wavefront sensor measures distortions and degradations experienced by the wavefront; the computer apparatus uses the measurements to calculate the optimal shape of the deformable mirror to correct the distortions and degradations. More specifically, the deformable mirror includes a plurality of actuators and each actuator is reshaped accordingly in order to reconstruct the wavefront forming the optical image. In order to perform adaptive optics technology correction, the shape of the incoming wavefront must be measured as a function of position.
For example, a telescope used to view a distant star is subject to atmospheric turbulence. The telescope includes a wavefront sensor that includes an array of small lenslets—such as a Shack-Hartmann sensor or a curvature sensor—which operates on wavefronts received by the telescope. The array of lenslets splits up the wavefront into an array of pixels or focal spots. The average wavefront perturbation in each pixel is calculated by a computing apparatus. This pixellated map of the wavefronts is used to adjust the deformable mirror in order to correct the wavefront distortions and degradations introduced by the atmosphere. The deformable mirror corrects the wavefront so that the reconstructed image appears sharp.
Certain current optical systems and methods must perform numerous and burdensome calculations to determine the proper position of the deformable mirror—specifically each actuator—to ultimately reconstruct the object image. These numerous and burdensome calculations may affect the vision and resolution of the reconstructed optical image. What is needed is an optical system and methods that increases the speed of calculations by which corrective elements such as deformable mirrors function, reduces the number of lenslets in an array and improves reconstruction time and focal spot quality. The present invention satisfies this demand through congruence reduction that formulates composite lenslets.